is in quadrant I, so
.
is in quadrant II, so
.
Recall that for any angle
,

Then with the conditions determined above, we get

and

Now recall the compound angle formulas:




as well as the definition of tangent:

Then
1. 
2. 
3. 
4. 
5. 
6. 
7. A bit more work required here. Recall the half-angle identities:



Because
is in quadrant II, we know that
is in quadrant I. Specifically, we know
, so
. In this quadrant, we have
, so

8. 
Answer:
Here is yours.
But next time, pls give it a try,bro!
Good luck!
Answer: 88
Step-by-step explanation: 77+82+73= 232. So you need an 80 for average. So what you have to do is 80x4 and that equals to 320. last step is to subtract 320-232 and you get 88. 77+82+73+88=320.